LED Lighting Control IC with Embedded Flash Memory Lookup Tables

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Solution Overview

Problem

Existing LED lighting control systems face challenges in providing high-precision luminance and chromaticity control due to temperature variations, aging degradation, and power-on time, with complex IC fabrication processes limiting their ability to meet advanced performance demands.

Innovation Solution

An LED lighting control integrated circuit featuring a nonvolatile memory, multiple lookup tables, a signal processing unit, a PWM signal generating module, and a driving module, which generates calibration and compensation signals to adjust current and voltage settings for precise LED control, including uniformity-recovery mechanisms for damaged LEDs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrical-erasable programmable read-only-memory (EEPROM) is used for storing lookup tables, then compensation data can be stored and retrieved, but the IC fabrication process becomes complicated

Engineering Contradiction:

Improvecompensation data storage reliabilityVSAvoidIC fabrication process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the memory type parameter from EEPROM to Flash memory, which allows for simpler fabrication processes while maintaining the ability to store and retrieve compensation data effectively. This parameter change resolves the contradiction by achieving reliable data storage without the complicated fabrication requirements of EEPROM.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent integrates multiple functions into a single IC chip, including the Flash memory for storing multiple lookup tables, the microcontroller for processing, and the output interfaces. This multi-functionality eliminates the need for separate EEPROM components, simplifying the overall fabrication process while maintaining compensation data storage reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple lookup tables are stored in nonvolatile memory, then compensation for temperature variation, aging degradation, and power-on time is enabled, but the device complexity increases

Engineering Contradiction:

Improvecompensation functionalityVSAvoidmemory and processing structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple lookup tables for different compensation types (temperature, aging, power-on time) into a single Flash memory component within one IC chip. This merging approach enables comprehensive compensation functionality while reducing device complexity by eliminating the need for multiple separate memory components and their associated control circuits.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the compensation data into distinct lookup tables within the Flash memory, each dedicated to specific compensation parameters. This segmentation allows for efficient storage and retrieval of compensation data while maintaining a unified, manageable memory structure that does not significantly increase device complexity.

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If compact design with more compensation functionalities is developed, then advanced performance demands are met, but the fabrication process becomes more complex

Engineering Contradiction:

Improvecompensation and calibration functionalitiesVSAvoidfabrication process

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent merges multiple compensation and calibration functionalities into a single integrated IC chip with Flash memory. This integration achieves compact design with advanced performance capabilities while simplifying the fabrication process by eliminating the need for multiple discrete components and their complex interconnections.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The IC chip is designed with universal multi-functionality, incorporating Flash memory for storing various lookup tables, a microcontroller for processing different compensation algorithms, and multiple output interfaces. This multi-functional design meets advanced performance demands while maintaining a streamlined fabrication process suitable for mass production.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS7999491B2LED lighting control integrated circuit having embedded programmable nonvolatile memory

Publication Date: 2011.08.16 EMEMORY TECH INC

AI summary

For providing a compact high-precision lighting control means to drive an LED lighting module, a lighting control integrated circuit is set forth to perform an accurate lighting control. At least one nonvolatile memory is embedded in the lighting control integrated circuit for storing a plurality of lookup tables. One lookup table provides related data for setting the driving currents of the LED lighting module based on spacing or pitch of LED disposition of the LED lighting module. Another lookup table provides related data to recover uniformity for different LED damage situations of the LED lighting module. The other lookup tables are applied to perform compensation processes on the driving currents concerning temperature variation, ambient light intensity, aging degradation, and power-on time. In addition, a signal processing unit, a pulse-width-modulation signal generating module, and a driving module are incorporated in the lighting control integrated circuit for signal processing and current driving.